Carlo Rovelli: Love and Quantum Physics are the Same | The Futurology Podcast

Hi and welcome to Futurology. I'm your

host Don Nakagawa. In this interview

between Claire Webb and Carlo Ralli, we

span the universe and explore the nature

of reality. Carlo is a proponent of

relational quantum mechanics. His bold

claim is that the universe from the

smallest to the largest cannot be

understood by studying its objects. But

rather we can only understand it through

its connections, its interactions and

its relationships. From particles to

people, from physics to philosophy,

nothing stands alone. This interview

covers his work, his theory of reality,

and how Buddhist cosmology may reveal

the secrets of the universe. And now,

let's go to the interview with Claire

and Carlo on Futurology.

Carlo Ralli, welcome to Futurology.

>> Thank you very much, Claire. It's a joy

doing this with you. I've joined you in

taking off my shoes. Um because this is

your habit during interviews and I do

feel more loose and comfortable.

>> It's my habit in life. I hate shoes.

>> Um Carlo, uh behind us is this beautiful

background of of Venice. Um you're

Italian, uh from Verona.

uh tell us about growing up here and and

how it's informed your philosophy and

your physics.

>> Verona is 100 miles from Venice. So this

is still home in a little bit a little

bit for me. Um so I grew up in this

region uh uh in a comfortable rich

postwar Italy

uh much loved by my family in a in a

rich country. Um and uh I think the

privilege of growing this way was also

that is a country that gave a very wide

education to to kids based on history,

on art, on philosophy

um on everything. It was very useful for

me for later my my scientific uh career

and also I grew up during the cold war

where the world was divided in two two

parts that were hating one hating one

another and describing one another as

horrors both of them

and uh to some extent Italy was in

between was not the only country in

between but was a country in between

because it was a major communist party

here which also was good because it gave

a double perspective on on the world.

But then I left Italy pretty soon. I

traveled a lot. I lived US, France,

Canada, now Spain, many places.

>> This doubleness that you talk about or

the desire to to be in the middle of two

things very much resonates with your

chosen field of interest. um quantum

mechanics. So, why don't you tell us

about

um what first got you interested in

theoretical physics and how

uh how you've been curious about the

very small world.

>> It happened quite late. Um I went to

university. I studied in Bologna.

Um oldest university in Europe. Um and

uh I enrol enrolled in physics uh I took

physics as a major uh not really because

I was particularly attracted by physics

but because I didn't know what to do and

uh my university years were years of uh

exploration of the world a lot of

reading a lot of traveling a lot of

friends a lot of experiences a lot of uh

trying different things were the 70s in

which part of the young generation was

very exploratory in terms of behavior

and uh and also ideas. Uh a lot of

discussion about ideas, a lot of reading

of philosophy, a lot of reading of

intellectuals. Um so science was I felt

that science was sort of the the new

knowledge of the new century and so I

needed to know something about it but I

I didn't go into it thinking I would

become a scientist. Then I stumbled

about quantum mechanics in a funny way

because um

of course there are classes courses in

quantum mechanics in the university when

you study physics but that's not how I

studied quantum mechanics. stud quantum

mechanics because of a misunderstanding

because my mathematical teacher um sort

of gave us pieces of mathematics to

study gave me group theory and I said

okay what should I do and he said the

applications to quantum mechanics and I

said but I don't know quantum mechanics

yet and he said well study it and he was

joking but I didn't understand he was

joking so I went home and spent two

months total immersion in learning in

quantum mechanics and it was best two

months of my life. for me to five or six

books and uh studied this fabulous

theory and uh more or less the same time

I got in love with general relativity,

Einstein theory and that changed my life

the two things because uh now I found a

problem a a a kind of knowledge that uh

uh completely captured me and fascinated

me because it was profoundly

Um,

let me use this word revolutionary.

And that's what I wanted somehow. I

wanted something else. Not the world

that I had around me. I wanted something

else. And there was something else

there. There was a

a discovery scientific so in some sense

reliable that the world is not the way

we look at it. It's profoundly

different. I was extremely fascinated by

that. I started doing less and less of

all the rest and just naturally spending

more and more of my time uh reading

about science and then I realized that

these two major steps ahead in the

knowledge of of the world uh were not

yet combined. So the problem of quantum

gravity was still open and I I said okay

this has to be done. tell us what

quantum gravity is and how Einstein's

equations of general relativity describe

spacetime on um cosmological scales.

Yes. Um ice and relativity

um was born as a gravity. Gravity is you

know things falling down and the moon

going around the earth kept by gravity.

Um I realized that all the Newton theory

was insufficient the light of what was

had been understood. So uh changed it

and gave us this fabulous theory which

is general relativity which understands

gravity in terms of um uh a different

way of thinking about space and time

with respect to Newton. So space and

time becomes dynamical fields become

things themselves that can bend and

stretch and uh it's a it's a marvelous

theory. It really changes your

understanding of reality. Um and uh it's

100 years old now

110 now. Uh but in the last decades it

has obtained spectacular confirmations.

So basically everything Einstein

predicted black holes gravitational

waves expansion of universe turned out

to be true true and then the other half

is quantum mechanics. Quantum mechanics

is a it's a theory about things um which

uh shows that things don't behave the

way we we we thought before. Um they

have curious properties. First of all um

they behave with probabilistic. We

cannot predict it with certainty. Uh

second there's a sort of granularity

discretetness at short scale. So light

for instance made by photons which are

little particle of light quanta that's

the name quantum mechanics and third

which is the most interesting thing that

things

cannot be understood just by themsel

they don't have just properties by

themsel the properties of things and

this is you said small things but in

reality everything just this is more

evident for small things things um have

properties when they interact with

something else. So we understand an

electron as in terms of the way it

affects something else and in fact we

understand everything in terms of how it

relate to something else. Which means

that to understand the world we have to

think in terms of relations

rather than in terms of individuals

having properties.

Um this is very deep. it took long to be

digested but I think is the core message

of uh uh the new physics but that's what

we're asking um what is quantum gravity

u the problem of um understanding the

the quantum aspect the quantum

properties of space and time is is still

open we have theories I my me and my

friends and and my colleagues uh have

been working on this um uh theory of

quantum gravity

uh for decades. It's called loop quantum

gravity. It might be right but we don't

know because it has not been tested yet.

So in one sense it's very conservative

as a way of thinking because it's it's

based on the idea let's we have

discovered something about the universe

quantum mechanics let's take it

seriously we have discovered something

about the universe generative TV let's

take this seriously what does this imply

together and it's very

it's very conservative but then it

becomes very radical because uh it means

that space has quantum properties and

time has quantum properties It is. So it

means that space is made by quanta as

this granularity and so is time. Uh but

not only that that space and time

themselves have this relational

property. They're not things by themsel.

They're ways in which various things

affect one another. So it's a it's a

really new way of thinking about the

world.

Um a lot of contemporary theoretical

physics is different. It's sort of based

on the same old conceptual scheme trying

to guess something new. What about these

equation can be changed? What about the

new particles? What about the world is

made by strings? What about the many

dimensions? What about the other words?

It's a I don't think it's good way of

going ahead understanding the world. We

understand the world either because we

have new data or because we take it

seriously what I have learned so far and

we try to work out the consequences

and this is a conceptual work. It's a

theoretical work but it's also a

philosophical work. Um so I think that

the physics of the 20th century it's

truly pushing us into a new philosophy a

new way of thinking. It's not completely

new. I mean it's ideas which were around

um but it forces us towards certain way

of think about the world and away from

other ways of thinking about the world.

The world is not made by things. It's

not entities out there. There's not the

being. The world made is is a flow of

things related to one another that make

sense by the fact that they're related

to one another and uh that we understand

by realizing not by looking for the

outside but realizing we are part of

this uh sort of network of relations

which is reality. And it seems to me

though that there's something different

about making a measurement of a

particle. Uh freezing it in time, let's

say, uh is an electron spin up or spin

down. Um your relationship

to that particle and knowing about that

particle is mediated by uh really

sophisticated

um technologies of perception.

That seems to me to be really different

than being in love. So, how do you think

about different kinds of relationality?

Or is every kind of relation made out of

the same stuff built on the same

principles?

>> Um, that's a fabulous question. It's a

great question. Um, thank you, Claire.

Um, it's both in my opinion. First of

all, I don't think there is any gap in

the world. Um,

title of my next book is going to be on

the equality of all things. So, I think

that measuring an electron um it's a

complic complex operation that um

involves the electron itself. Poor poor

guy is there and it's real. It's it's

something there. uh but it interacts

with an apparatus. It's a complicated

apparatus. There's a lot of technology.

We read it in terms of our theoretical

ideas. So what we're really doing is

applying theory to some phenomena which

are out there and that that's reality.

We're describing reality. Um it's

complex relation of things. Now when

when we when we get in love uh it's

completely different uh set of relations

which are around but it's also a complex

relations of things and like electron it

can be described in different manners.

Um I can be a poet and express or try to

express uh the unique feeling of um

happiness, excitement, absoluteness,

total change which is to get in love. I

can be a medical doctor and describing

what happened in my body. I can be a um

a person studying the the the the neuro

neurological aspect of that or the

chemical aspect of that. I'm not I'm

always describing the same phenomenon.

It's not one is right, one is wrong.

There are level of descriptions. Some

are more appropriate, some are less

appropriate. Uh some work well, some do

not work well. Um but it's always the

same thing happening. It's just reality

happening. And reality happening is just

reality happening. Whether it's a moon

going around the earth, a ball falling

on the ground, or me getting in love

with a person, that's my view of the

world. There's a deep equality of levels

between between all the things. And

there are many languages we have to

describe um reality which are coherent

with one another even if they are

distinct. Can you talk about this

relationality

uh from the perspective of your new work

on uh consciousness? What you're

describing to me, Carlo, is

you're you're a physicist. The world is

real. The world is material. Love isn't

just um oxytocin and serotonin and and

endorphins um dopamine flooding the

brain in particular ways. So, it's not

just chemistry, but it's an entanglement

of relationships that include hormones

and chemistry. How does that all link up

to the conscious experience of knowing

you're in love or enjoying poetry? Is

that all materialist, but it's just

different layers together?

>> Yes and no. Once again um to say that if

some complex

situation obey certain simple uh laws

doesn't mean that we understand it

because uh the the simple laws are just

a some regularities that reduce the the

infinite possibility of just logical

facts. So saying if I get in love with

chemistry, it's just silly because also

a a glass of water is just chemistry.

That's not interesting. What is

interesting is that chemistry of the

glass of water is very different than

the chemistry of of a person in love.

Okay. Now, do we know the language for

describing specifically the chemistry of

a person in love? No. Only a little bit.

Only some bit little chunks. You've

mentioned some of them. But the

complexity of going on far um goes

beyond what can be said in chemical

terms and even more what can be said in

uh physical terms. So to say that

everything is when we get in love

everything is chemistry or our

consciousness everything is chemistry.

First of all why chemistry I mean why

not physics then or why not basic

biology? I mean all all these levels are

good but all these levels are completely

insufficient. So no they do not describe

what happens when we are in love. We

cannot uh we have we need another

language. We need another set of

concepts. But we make a mistake if we

think that

um there is a metaphysical gap which is

uh sort of breaking the sort of

underlying description. And now I come

to your question about consciousness.

This brilliant

um American philosopher, Australian

philosopher is David Chalmer who has

separated the famously two problem of

consciousness. The easy problem he

called the easy problem and what he

called the hard problem and the easy

problem is everything can be in

principle said about the phenomena of

consciousness if we could understand all

possible signs uh about it. all possible

physical, all possible psychology, all

possible all everything that could be

that and then he says suppose we could

have um solved all that there would

remain an open problem which is what he

called the hard problem of consciousness

>> and the hard problem is understanding

what according to David Chalmer's what

qualia are that

>> um that that calculating the distance um

between you and me would be very

straightforward with a physics well with

a ruler

>> but figuring out what is red.

>> Figuring out what is red or the taste of

chocolate or the feeling of being being

in love. These qualia are irreducible

phenomena in the world that somehow

within Talmer's framework elude

quantification, understanding,

parsibility.

>> Exactly. And I think that um the

distinction is brilliant. So what could

be understood so to say scientifically

from what would the problem will remain

open after all that. But I think David

Chalmer completely misnamed these two

problem because what we call the easy

problem is nothing easy there. It's

enormously complicated. It's extremely

complicated to understand what happens

when I taste chocolate or even more when

I uh when I'm in love or when I have a

emotion one kind of the other. So the

easy problem is hard but what he calls

the hard problem namely whatever remain

open after I have uh understood that

that's easy in my opinion that's

extremely easy because that's a false

problem the answer to that problem is

the answer that vikstein vidkstein

um gave to the question about what is

the great riddle the answer of the

riddle is that there is no riddle

there's no problem. What is the qualia

of me tasting chocolate? Well, it's

whatever happen in me when I taste

chocolate. It's nothing else than that

>> to which I give a name which is

chocolate. And if you say well but that

particular feeling well that particular

feeling is a particular thing that

happens in me. We do acquire

capacity of distinguishing qualia as we

uh live right. I mean you I don't know

you drink wine it tastes like wine and

then you you drink more wine and you

realize that Keianti tastes different

barolo and then you start distinguishing

different kind of Keiantes. Uh

>> is this a plug for Keianti?

>> Uh yes.

>> Yes. I I prefer barolos but I I love

this. Okay, great.

>> Oh that's a subtle discussion.

But Carlo, can you tell me why measuring

the distance between the two of us with

a ruler is harder than you knowing what

chocolate tastes like?

Well, you're saying that they're saying

that they're more immediate to us. Um,

there are many things which are more

immediate to us because uh um the easy

problem is complicated.

Namely, um when we say consciousness,

which by the way, it's a very modern

uh notion. Um nobody talked about

consciousness a few a few centuries ago.

Um if not in moral terms, which is not

what we mean together. Consciousness

doesn't even have good translation in

Italian.

There's no word for that. The problem

with consciousness is that everybody

means something else. Okay, for some

people to be conscious is like to be

awake versus to be asleep. For other is

to have to perceive. For other is to

have a self idea of oneself.

To other is just a awareness. Um just

being aware I'm I'm aware that you're

there. I know that you are there. So I

have some awareness. So therefore I'm

conscious. To others is even something

more generic. Is a vague sense of

distinction of me from the rest.

It's for others is the capacity of using

the noun I okay or me. So people talk us

this were the same things but these are

completely different things right my my

cat certainly has awareness of a lot of

things and has a a rich emotional life a

sensory life which is compared to mine

but I don't think spend time reflect

self-reflecting about its own identity

it doesn't care it cares about mice and

and and me and and and and

being pet and sitting in the sun so The

consciousness is extremely confused and

vague term and we are making a big deal

of it. We shouldn't we should just break

it apart in a variety of different

notions which are all interest to study.

For instance uh in our own life

we have the experience of being awake or

asleep and sleep with dreams sleep

without dreams. Oh that's super

interesting. What's the difference

between this? what different is going on

in our brain, in our body, in our

relation with the outside

um in these cases. That's a good

question. Okay.

>> But do you think there's something

uniting um when you break out these

questions of consciousness? Is there a a

through line? Um for instance the cat

not having

uh consciousness

you were saying is about self awareness.

So

>> the cat doesn't reflect about itself

have self-reflection.

>> I imagine it doesn't.

>> Yeah. So is this quality of

self-reflection essential to the quality

of consciousness no matter how we might

study it?

>> It's a matter of definition. It's like

is having a cover essential for a book?

Well, yeah. Do you want to call book

book without cover? You want to call it

book is up to you. It's not there's no

the essentialism.

It's a wrong idea to ask what is the

essence of something. There's no essence

of something. There are names we give to

classes of phenomena. These names are

completely arbitrary. We're interested

studying how these phenomena are, how

relate to one another, what we can say

about them. Not to ask what is to be a

book. There's no what is to be a book. I

mean there is a You know somebody wrote

stuff on paper and printed it and we

call them book. Now a notebook is a

book. Well yes and no. I mean it's not

that's a bad question. So where where do

we want to put the label consciousness

is totally arbitrary.

There's no the essence of consciousness.

There are many phenomena. All of this

can be understood. There is no mystery.

There is no riddle.

>> So consciousness as a category is laden

with a particular

historical meaning. um also a particular

uh social meaning now. Um so while it's

a academic category now that

intellectuals can can talk about and

have conferences about it wasn't really

something that Buddhists were naming as

such uh thousands of years ago. So can

you talk about the history of

consciousness and how you see the

category of consciousness now amidst

that history?

>> Yes, you touched many things. Um

one aspect of this and let me just fall

back to books for a moment. Um is that

when we think about our own conscious

there's a deep linguistic aspect of it.

So one thing I find fascinating it's a

question not what consciousness is but

how much uh this extremely developed

language that our species has developed

as a species not as a recent

civilization we don't even know since

when this is we're very confused about

the origin of language how much this has

changed um our perception of ourself so

the question what's the difference

between me and a cat it's some extent

connected to language and so um how much

giving a linguistic uh account of

reality uh changes the way of perceiving

reality that's that's a that's a great

question for me um and staying still on

the on the long term sort of humankind

um time scales um no doubt we are social

animals um erh uh like our cousins a

great apes uh but much more so because

we make a much larger uh structure. So

no doubt uh the language and uh uh our

brain function have developed also in in

relation to this

um to this complicated social relations

we have. So I think a lot of my sense of

self is social.

I personally

think that

when I mean when I think about me, what

I'm really referring to is how my

friends, my mom, my lover, my all the

people, my enemies look at me. And this

um and is the way I look at them. I know

how they look at me. And this back and

forth between images that construct our

social identities. So the self it's it's

very much a social build up

in in some sense. Okay. Um which doesn't

change the fact that animals which are

not social have some sort of self

different different kind but but very

different I think for for this re

reason. Now historically

uh we know I learn that the the way

different civilization described

um the inner working of a person has

changed a lot. Um we know famously that

in Homer at in the early Greek

civilization there are no words that

correspond to a person directly thinking

meditating um deliberating

having ideas taking decisions in the

Iliad when when describes somebody

having an idea it's always a god that

comes and and and gives the person an

idea so it's a different language for

describing what happens and the modern

uh um the modern western notion of self

and conscious is really modern. Uh maybe

it has a root in St. Augustine. So there

are some root in late antiquity. Um but

there's nothing like that in in

antiquity even if it is extremely

developed cultural and intellectual

tradition of course around the

Mediterranean. China and India as far as

I know are different and different among

themselves. India is closer to uh to the

west to the Mediterranean. It had more

relations of course back to millennia

ago. Um and Buddhism had a long

reflection about the self which

interesting got in two different

directions. One is um a lot of attention

about the self. there's a large very

developed Buddhist psychologist

psychology traditionally um but also in

the opposite direction there is the idea

that the self is illusurary that there's

no self um which an idea I like a lot

and I think I like a lot because it

heals us from this illusion of

essentiality I am this um cartisian or

better hideer idea that we have a direct

intuition about being because we are um

I think there is something deeply wrong

there in the sense that it gives a

priority

uh to to to consciousness the first

person which is illusion silly right

when when when we put put ourself in the

center we know we're making a mistake

right we're little things in the huge

cosmos there are billions of galaxies

and galaxies billions of stars and then

there's earth and the earth is a it's

very big and we know don't even know

what happening in its center and there's

a sky. There's a s teeny teeny layer

which is the the biosphere at the

surface of of the earth where there's

this complex phenomena happening like

complex phenomena happening all over the

universe. The little waves on the sea

and one of these is us. That's what we

are nothing more than that. We make a

big deal about that you know we we get

angry we make wars with all the stupid

things when we are just uh little

ripples on the floor. That's how I I I

think and I hope that thanks to modern

science, thanks to modern reflection,

thanks to cross-cultural

dialogue, we could use this uh sense of

irrelevance of ourself to uh give less

importance and go away from this

essentiality, this absolutism which I

think is devastating in our lives and uh

accept the lightness of a view of the

world in which we're just part of this

network of interactions.

>> How's relationality uh meaningful make

meaning in in the quantum world in

quantum mechanics?

>> Yes. um this this large angle view of

reality I was uh referring to uh for me

to a large extent emerged by think about

quantum mechanics specifically and since

the '9s I've developed a um a way of

thinking about quantum mechanics which

is called relational quantum mechanics

um which today is more and more this

part of the main discussion about

interpretation of quantum mechanics

Quantum mechanics is a strange theory,

right? Because it's super effective.

It's used in technology all over and yet

it's very strange. It's very

>> It was developed um in the 1920s in

particular and really caused a major

shift in in how physicists saw the

world. Yeah.

>> Yes. And in fact, now we are exactly 100

years from the the group of papers that

established it. Um quantum mechanic was

born in uh four or five papers uh that

came out within a within a year. Uh the

first one was by Heisenberg and then by

born and Jordan B Jordan and Heisb and

Iraq and uh it's quite astonishing

because five papers in um in a short

time that's it that's quantum mechanic

then it was developed applied to

everything except gravity. So the point

is that uh the questions are clear the

application are clear but what exactly

the theory says about the world is very

confused and the discussion is going on.

There are conferences with physicists,

philosophers, mathematicians um having

different opinions of how to think about

that and there are a number of

possibilities on the table which are all

good. And what and what is so confusing?

What what kind of existential confusion

did uh quantum mechanics first give rise

to?

>> Because it doesn't describe what

happens. It describe what you see when

you look. Okay? And if you look at some

moment, it gives you the probability of

what you're going to see if you look

after some time. And if you try to fill

in a story, it doesn't fit. So in

Newtonian mechanics, in classical

mechanics, it is completely knowable

where a ball would land. Um if I threw a

if if I threw a football through the

air, um I could calculate the time, the

distance, the arc. Uh things would be

certain. quantum mechanics. One of the

foundational paradoxes of of quantum

mechanics um is the more you know about

momentum of a particle, the less you

know about its about its position. And

there's something deeply odd about this

that goes against what we see every day

and can describe every day in the

day-to-day world.

>> Absolutely there is. And it's not just

the fact we cannot predict things with

certainty that okay, that's our life. Of

course we cannot predict things with

certainty. We do not have enough data.

It's more than that. Is that if we see a

particle in a point and then after 10

seconds we see another particle in

another point and we say okay the

particle has gone through this path in

between.

This does not work. If we work this out

we find contradictions.

So it's more complicated. The particle

doesn't go from here to here. So

disappears and reappears there in some

sense. So the theory is not about how

things are at some time at every time

but they're only how things affect

something else. Now at the beginning

people were saying oh how they are

observed but of course it's not because

we human observe them. We humans are

just stuff like anything else from a

physicist perspective. The point is that

how things affect other things,

it's a crucial part of the story, not

how things are. So the theories about

how things affect one another and how

what what's what because of that um what

things can know about one another

because they can have records of what

happened before. And this is very

different than saying how things are. It

takes away the R. It takes away the

being. It reduces the being to

relationality.

Now people try to make sense of this in

different manners and uh let me mention

two or three which are not wrong but I

think they're not good different thing

they're not useful one is to say oh well

there are things that happen we just is

in they're invisible to us is a big

complicated world of hidden variables

that are in principle hidden you can

always add pieces of reality to make

sense of it even if there's not access a

Second one is to imagine that there's

multiple world. We you and I are just in

one branch of a immense universe in

which the copies of yours eyes and this

for some technical reason make things

more sort of metaphysically

clear but to my opinion in my opinion

absurd. I you and I are here now they're

not doesn't make sense think about other

copies of us.

A third possibility is to think that

quantum mechanics is just wrong. Oh,

perhaps it's wrong, but it's wrong in a

way that it's going to be replaced by a

theory is not so strange. But I don't

think so because usually when science

goes ahead, theories are replaced by

thing theories which are more strange,

not less strange. So where does it leave

us? I think it leads us to relational

quantum mechanics which is to the idea

let's not try to fill to add to quantum

mechanics an ontology a story how things

really are because the question how

things really are is a meaningless

question what does really mean I can ask

how can I understand better I can say

look this is a table but if I study

better it's made by atoms true that's a

better understanding but I cannot say

yes but what is the ultimate description

the ultimate description the ultimate

doesn't mean anything the most

fundamental way what does fundamental

means okay fundamental is a is a

relative term there's something which is

fundamental for one perspective

something fundamental for a different

perspective

so I think what quantum mechanic this is

relation quantum mechanics what quantum

mechanics is telling us is that we can

give a description about the world but

it's our perspective ive and it doesn't

necessarily match with some other person

or another object

description of the world. So phenomena

relative phenomena relative to one

system and the same set of phenomena

relative to a different system might be

different. Now these perspectives talk

to one another because I can ask you

what have you seen? So they're not um

they're not we don't live in islands

that don't talk. We talk all the time

because the perspective themselves are

of physical just the way I am. Okay. But

the idea of having a description of the

world which is a absolute final

universal the god view of the world

doesn't play any role for us. It's not

accessible.

It it doesn't make sense. It's a it's an

open riddle whose uh answer is that

there's no riddle. Forget about that.

Let's talk about the perspective. Let's

talk about the information the system

have about one another. We are physical

system like any other. And that's a way

of understanding quantum mechanics. And

that's of course that's the relation of

quantum mechanics. It's a way of

understanding quantum mechanics which

inspires and resonates

with this general view of the world as

perspectival

um a non foundational view of the world.

um which I mentioned before

which uh if I have to find traditional

thoughts in philosophy

uh it's not totally new of course you

can find in philosophy some bits in

western philosophy but remarkably clear

expressed in some chapters of eastern

philosophy

um in particular in some aspect of

Buddhist philosophy I was particularly

struck by Nagajuna who was a very very

similar suggestion. So discard any

questions about the ultimate reality. Uh

just talk about the the apparent reality

things make sense um in relative to

other to other things.

>> So I want to get to that um very soon.

But one could say an example of

relational

uh ways of being in the world which

quantum mechanics is one description. Um

if you take this table from a quantum

perspective uh things are so far apart

nothing is touching each other. If you

take it from um a geological perspective

you could describe this table in terms

of um marble that was probably quarried

around here. If you're taking it from a

um like a molecular perspective you

could describe the molecules of of that

rock. Um, if you're a functionalist,

this table is something that is holding

our water glasses uh and and our books.

Um, so these are different descriptions

of reality from different perspectives

that rely on at least two objects in the

universe. Um, and perspective is

very important um in understanding what

that relationship is. You always have to

have a perspective.

>> Yes, your example of the table is very

good because uh all these perspectives

on the table are um meaningful and

interesting for us. Each one give us a a

good story about the table and the point

I want to stress about the table still

are two. One is that some of this

perspective more obviously and some less

obviously you're never really talking

only about the table. Okay. Uh you can

talk about this function of the table

which of course is to hold the glasses

there and to put sang which of course is

a very good account of what the table is

but not by the table itself. The table

in in full immers immersion in a

civilization of ours where it plays this

role. Okay. Uh you can talk about the

color of the table but the color of the

table is not a property of the table. Of

course it's the space of color is

threedimensional. We know it very well

how to describe it. But why is

threedimensional? Because we have three

receptor in our eyes. So you talk about

the color, but you're also talking

implicitly about our eyes and also about

the social context of what this color

is. Going back to uh Homer, your example

of Homer describing the wine dark sea.

Uh, we presumably had the same um well,

we did have the same number of cones and

and the the physical and the optics of

our eyes are exactly the same as as

people um more than two millennia ago,

but descriptions of colors are socially

based. Homer did not say that the ocean

is blue. He described the wine dark sea

over and over and over again.

>> Yes. So it's um you you to describe a

single object you you're implicitly

referring to other things around it. But

the interesting thing is that when you

go down to a physical description also

okay because when you do a quantum

mechanical description of the table you

cannot talk about the table by itself.

You're talking about the measure quantum

measurement of the table which are

interactions of the table with an

apparatus. So in a sense we always knew

then in take talk about the table we're

talking about also something else but we

were hoping that down there there's an

ultimate table which is physical and

it's not true. So there's no ultimate

table table there's just table from all

possible perspective and uh our best

knowledge of this table is not one of

these it's as many as possible of this.

Now let's go to Nagajuna.

Najuna um I met him um not long ago

maybe 10 years ago um it's considered a

major philosopher in his in in in

Buddhist philosophy classical uh couple

of millennia ago a bit less um and uh he

has a book um in which he uh

describes in detail what you call

emptiness the empty nature of um um of

things in which um a lot of things are

going on. But from from my perspective,

one of the central ideas is going on is

precisely the impossibility of um um

accounting for one thing whether it is

an object, whether it's a time, whether

is knowledge, whether it's whatever idea

you have just by itself. and understand

that if you try to isolate one thing

you're you're do he's a logician you're

you're doing something contradictory you

always understand things in terms of

something else

>> so but why is that um emptiness

>> emptiness is a is a technical term for

najuna it doesn't mean non-existing it

means um uh absence of autonomous

independent existence okay so

naju never says something doesn't exist

It says it it it it only exists

depending of something else. Okay. And

then this leaves a strange uh

circularity, right? Because if something

depend on something else where you hang

on. Okay. And this is the key point I

this the first key point he says uh and

and I think it leads us to thinking that

there's nothing wrong with the

circularity. Um he talks about like

everybody he talks about um the apparent

world and the ultimate world. Okay. The

apparent reality, the ultimate reality

and the apparent reality is no. This is

a book. It's white hole blah blah blah

because of I read it this way the way

what is the ultimate reality. Well,

there isn't. That's the point. There's

no ultimate reality. But then

he call emptiness this quality this

property if you want of things of not of

of not existing if not independence of

something else. But then the point where

the book really got me is uh toward the

end there's a chapter in which in the

slogan can be introduced to the

emptiness of uh emptiness

uh emptiness is empty. So he warns the

reader very clearly that if you take

this story as the ultimate description

of reality, you're making the same

mistake as if you take something as the

ultimate description of reality. Right.

So there's no ultimate description of

reality and this is um again this is a

spectacular idea. It resonate with the

best of Vietkashan in my in my opinion.

The answer to some questions is that the

question is just wrong. Um asking what

is the ultimate structure of reality?

It's a confusion is our language that

tricks us or our mind or whatever that

tricks in that. So uh the self the mind

is not the ultimate part of reality.

Matter is not the ultimate part of

reality. Information is not the ultimate

aspect of reality. Computation is not

the ultimate aspect of reality. Um uh

perceptions, phenomenology is not

everything is not wherever you we can

organize reality in structures of course

and put something at the bottom of each

structure. But then there's always a

blind spot that bottom which you

sometimes very easily understand that in

terms of something else. So you're in

these circles. But the circles is the

best we can say about the world. And is

this because uh oh there is an unknown

mysterious reality alanton

which is unaccessible.

No there's a better way of thinking

about that. It's because it doesn't mean

anything to ask what is ultimate

reality. That's what I what's fascinated

me in the garden. It strikes me, Carlo,

that the emptiness of emptiness is a

beautiful description of a pre big bang

universe.

>> We don't know anything about the pre-

Big bang. I think, you know, this is

another thing we we're afraid of saying,

I don't know. I mean, both personally

and uh and and culturally and and as a

knowledge, so many things are so easy,

right? What happened before the big

bang? But we don't know. Okay, maybe

nothing, maybe something, maybe a

bounce. We can study it. It's not that

we we know that we cannot know. We don't

know if we will know or don't know. Um

for specifically about the big bang,

there is in loop quantum gravity a lot

of calculations that suggest

um there was something. So we can tell a

story of the other side of the big bang.

Um but this is science and the

scientific

way of trying to get better

understanding you you make you make

hypothesis but then you have to test

them. So my my my my work in science is

not just to make hypothesis about

quantum gravity and from quantum gravity

how the world could be but also try to

find ways to test them. In a Gargna's

framework within this emptiness, you

need a relationality.

Um, you need an observer. Uh, but the

self,

a soul, we might say, uh, he thinks

about that in a really different way

than, um, modern scientists usually do.

A codified self. I have a sense of self.

What I did yesterday, what I'm doing

tomorrow. Um so within your framework of

relationality that's very much inspired

by um Nagarjuna's what is the self?

>> Yeah I would I would try to answer um

using a terms but also a little bit

using charmer terms

if you ask what is the ultimate nature

of the self. Okay so what is the self in

itself? Um I think I I find today a

clear answer clear convincing answer

answer there isn't there's nothing like

that. Okay. Uh which again is a comedy.

Ern uh used to say there's no self

there's no I. Okay. Um one could say

using bad words it's an illusion. Okay.

Uh and one can tell stories about how

this illusion could make up. For

instance, um I and let me by I mean my

body here in a in a in in a simple

sense. Okay, I need to have information

about the external and make models of

the external to be able to predict

what's going to happen. So I do that for

for the bird, for the rain, for the

water, and for you. Okay. So I and since

we're social animals, we build strong

internal models of other human beings.

So I know what I do because I I I see

you smiling. I see you sitting. I want

to predict what you're going to do next.

I want to interact with you and so on.

But then of course I realize that you

know in this social interaction there

isn't just you and him and her blah

blah. There's also another guy. It's me.

Okay. So it's me. It's me. I mean what

is it self is just the self in the most

trivial sense. I mean this piece of

flesh which is thinking and doing stuff

with all its internal. That's what the

self is. Is me. Nothing else. There's

nothing mysterious in that.

There are philosophies, there are

traditions in which enormous importance

is given by this uh uh centrality of the

self. I I find them badly misleading for

understanding the world. Me is just what

happened in my brain. That is a name I

give to what happened in my brain which

has a remarkable

way of thinking about itself and unity

for structural reasons because bodies I

cannot split my body if I if we were

animals which I can split in two and go

in different things I would have very

different sense of self of course so

it's just a reflection of the unity of

my body but also I think a reflection of

the need of the enormous amount of

activity that is in our brain to have a

centralized the

system of processing for arbitrating

between different needs that come from

the body from from outside. So it's not

strange if I had to uh you know um

program a computer that needs to go

around and do stuff. Uh I I would put a

special routine that says here think

about yourself and what you're doing and

just focus on one thing so you take the

non-contradictory decisions so you will

have a self. That's what the self is. So

fundamentally I think the best answer to

what is the self is nothing at all. Uh

in the apparent reality in the in the in

in the part of reality that can be

described then we can say plenty of

things about our sense of self which I

just did how they come socially how they

come neurologically.

So that's would be my answer in terms of

um the simple problem easy problem

the self we can say a lot of things how

we develop this idea if we ask a

question about the a fundamental entity

metaphysically fundamental entity about

the self I think we are misguided

>> so Carla what is your theory of

consciousness

>> I don't have a theory of consciousness

but I have a number of ideas

um that I think could be part of the

puzzle not of the hard problem of

consciousness of the easy problem of

consciousness. Um the first uh remember

I'm a physicist. So what I would love

it's a way of connecting the levels

the physics with the languages the the

description that we have in terms of

higher level knowledge. And the first

key idea that separates these two worlds

uh these two ways we have to describe

the world is meaning right it seems that

in physics there's no meaning right

things are are there while when we talk

about our mental activity our conscious

activity things of meaning of in in all

possible senses so what is meaning where

does meaning come from um there is an

idea widespread is that meaning is

incompatible with physics cannot come

out with physics and I think is wrong

because uh there are two remarkable

discoveries of science in the last

centuries I'm talking about couple of

centuries which together um tell us what

is meaning

um and one is uh the realization that um

information is a key tool for talking

about reality and that information can

be described in pure purely uh physical

terms information is correlation. So um

if you correlation is when you you know

that by looking at one thing you know

something about the other

>> and what's information

>> it's just correlation so far just okay

by by information I mean correlation

okay

>> um suppose you have uh two balls and are

connected by a chain and you see one

ball there and you know the chain is is

is short so you know that the other ball

is nearby so this ball has information

about the other one. Okay? Because

they're correlated. If one is here, the

other can only be here and not

elsewhere. So the two positions are not

independent. Or suppose you have a coin

and one side of the coin could be head

or how do you say in English?

>> Yeah, tails.

>> Head or tail. And the other side also

can be head or tail. So this can be

two-way. This can be two way. 2 * 2

makes four. No, it's not four. Because

if one is tail, the other is head. Okay?

So one has information about the the

other one. If you see on the table, you

look at one, you know about the other.

So one has information about the other.

They're correlated.

Correlation is all over. The world is

full of correlations. Okay? The things

know about each other in this trivial

way, physical way. Okay? But now um we

know that uh life can come about um and

and and happens and we know the

biological systems and biological system

are systems even cells

systems that have the capacity of

reproducing and surviving and because

they have the capacity of reproducing

and surviving they survive and and there

are many of them and that's Darvin major

idea so

system have an sort of intrinsic builtin

purpose not because uh somebody put

purpose into them but is a feature of

them such that they allow them to

reproduce. So everything that contribute

to reproduction or survival it looks

like a purpose because it justify know

we have eyes to see. Okay. So on so now

when you mix put the two things together

something magic happens and very

beautiful. Namely some information that

a biological system some correlation

between the biological system and the

exterior are just random correlations

nothing

meaningful.

But some information can be meaningful

if it contributes to survival and

reproduction.

Right? For instance, um if I uh I'm

walking the mountain, there's a fall a

stone coming down, I see the I I move.

Okay. So when I see the stone coming

down, in my head there is something

correlated to the position of the stone.

Okay. Now imagine you take the same

situation and you think there's no

correlation. Then I don't move and I get

crushed. So that co that particular

correlation is a huge survival value for

me. It increases my possibility of

survival. That's what is meaningful. So

it's correlation that has survival and

reproductive value. So this is purely

physics. You can you can just build a

you know balls that bounce and construct

systems that reproduce which we think is

possible. chemistry that does that and

suddenly there's information which is

meaningful. So correlation which is

meaningful which is meaningful

information relation let's build meaning

okay and I think that this sort of

construction step by step

um can be allows us to connect the

levels and so that nowhere there is

magic nowhere there is a gap

um the second key ingredient

um that seems to differentiate different

um level of reality is agency. Right? So

we talk about agency,

different meaning, different senses, but

often we have the idea that agency

is something spontaneous that allows us

to work in a non in a way that

incompatible with the with way with the

ways of of physics, right? And I think

that's an illusion because we can make a

sense of what is happening

when we say that some system is an agent

in purely physical terms and I think

that what a physicist can contribute to

dispel the illusion of some gap in in

reality. So one of the things I've

developed is thermodynamical theories

um in which you can account of what

happens in a system when we call it an

agent and to show that this is uh not

only consistent with with the laws of

nature but is also uh makes sense um

thanks to the law of nature in

particular to thermodynamics that that

sort of drives the the the the

biosphere.

>> To to back up a little bit, um what do

you see as the relationship between um

agency and instinct? Um if you put your

hand on a hot griddle, um you have this

embodied response, pain. Um and perhaps

you learn as an agent not to do that

again. Um when you're seeing an

avalanche coming towards you, uh you

run. But how conscious is that decision

to run? And how much are you acting as

an agent versus how much are you acting

on instinct? Do you see the the two

concepts as identical?

>> I see a degree a degree of complexity in

our own reactions. So um if you if you

tell me are you do you want to come to

Beijing next year? What happened in me

is not the same thing as I touch

something a hot what happened in me is a

much more complicated thing because this

information goes to my memory stored is

compared is a complex deliberation

process it's a long deliberation process

at the end of which I decide who else

but I decide it means a deliberation in

me decides and when we when what we do

depend on a complicated process

happening in us

like a deliberation and you spend the

night saying should I do that should I

not do that should I take this job

should I not the night a week should I

take this job should I not um that we

call deliberation that we call our

agency and the subtle confusion here is

that people say oh it's not you to

decide because there's a process

happening in you but I am those process

so when I when I say I decide I am that

process process and all the other

processes. So of course I decide I think

that there's a misuse of language is

very common people tend to say uh if you

understand something then it becomes

illusurary which is completely silly

right if you understand what happened

when you take a decision it doesn't mean

that you're taking decision illusory it

means you understanding what happened

when you take a decision if you if we

understand what we call free will it

doesn't mean that we don't have free

will if we understand what it is that we

call consciousness. It doesn't mean that

consciousness is an illusion. It's just

a name. Okay? When um Copernicus

discovered that the earth does not the

sun does not move in the sky. Okay? He

didn't show that sunsets are illusions,

right? Because sunset is a sun setting.

So sun moving down, but the sun isn't

moving down. So is is sunset an

illusion? No. Sunset is still sunset.

just is not what we thought it was. So I

think we use the right word for

describing the world. There's nothing

illusion in the world.

Consciousness is not an illusion. Uh

free will is not an illusion. Agents is

not an illusion. But each of these

things we can understand them better in

terms of other things. And to wrap it up

with the beginning, we understand things

in terms of other things and not in

terms of ultimate things. Carla, you've

been talking about information as

correlation. What about causation

and your explanation of agency

uh with regards to the second law of

thermodynamics?

Um this is a topic on which I've I've

worked a lot in recent years um in the

following sense. There are a number of

phenomena

uh which are very important for us which

are time oriented very much time

oriented. uh agency is one right so we

decide the future we don't decide the

past okay we can decide where to have

dinner tomorrow we cannot decide where

to have dinner yesterday so there's a

profound orientation in agency and also

we talk about causes and effect

uh meaning that the cause come first in

time the effects come later okay uh I

can say oh there was a I don't know

there was a earthquake And then the

that's why that house is destroyed.

None of us would say uh oh look um that

house is destroyed and and that caused

the earthquake. Everybody will say no

come on that's silly. So the effect

comes after the cause. Um our decision

affect the future and not the past. Now

where does this kind time orientation

come from?

uh because uh as I claimed uh there's no

gap in nature and so everything should

be consistent with the laws of physics

and the laws of physics notoriously uh

don't distinguish the past from the

future. So where does it why is is is

why there are this orientation in this

phenomena. Well, the answer it's uh it's

uh not immediate. Um but there is an

answer and it goes through the general

orientation that we saw we see in nature

which is described by the second law of

thermodynamics

the the growth of entropy. Um the laws

of the fundamental mechanical quantum

mechanical generativistic laws of of

physics are um time reversal invariant.

They don't distinguish past from the

future. But this does not mean that the

solution okay are time reversal

invariant. We live in a solution somehow

the world is described by a solution of

these equations in which the past is

different for the future. Okay. And it

is different for the future in a very

specific way which is this constant

growth of entropy. Okay.

>> Entropy.

>> Entropy. So the the state of the

universe in the past was very low

entropy. We understand that very well.

We don't understand why it was low

entropy. But if you just accept the idea

that it was low entropy, it follows that

entropy glows as things happen. Some

phenomena happen in one direction and

not in other.

>> It's easy to break an egg. Um but it is

statistically extremely unlikely um for

the universe to put back the molecules

in the same way that before the egg was

broken.

>> Exactly. So statistically it makes sense

that things go where there more

possibility of being. is very intuitive.

It's very clear. What's not completely

clear is why things were in the past in

a special state. But let's accept that

for in the past were in a special state

and so therefore you know X breaks they

don't go together. Um but now the once

this is given the question is how it

comes that given the second law of

thermodynamics you know which is simple

gas expands things break and don't go

together. Uh it's very intuitive. How do

you go from here to I can decide where

to go

to dinner tomorrow and not yesterday?

Okay. Or how do you go from here to um a

cause affects the future and not the

past? That's not direct. Okay? You need

a story for that. You need to understand

the physics of agency and the physics of

causation.

And this can be done. I'm not going here

in the detail of of equations of formula

can be done. Uh there is a story one can

tell. So one can show in which precise

sense um given an approximate

description of reality the second law of

thermodynamics implies

that um position goes in one direction

or the other. However, in doing that,

um something subtle

uh comes out which is that we need to

fold into the story

um our own time orientation. Okay. And

that's a beautiful part of this uh of

this. I wish I had more time to describe

it a little bit more in detail. Namely,

it is true that we live in a time

oriented world. in a world where uh eggs

break and and uh glasses break if they

fall down and vice versa. But it's also

true that we are time oriented things.

Uh all biological things are

dramatically time oriented. Uh not for a

strange reason just because we are born

on the surface of the earth which is

near this burning star which so we get

all this um high energy photons from the

from the um from the sun and then we

radiate but the the the energy we get is

much more low entropy than the radiation

that we give out. So we we live in this

flu of entropy. We are entropy creators.

Um living being is an entropy creator is

a burning of stuff. A candle is an

entropy creator. So the biosphere is

time oriented. It's time oriented by by

its very nature. Okay. The the the

metabolism is raising entropy. So it's

is a and so are we. And our thinking is

time oriented. We cannot think backward

in time. Okay. Why? Because we are a

process which is time oriented. Our when

we think when you think hard your head

become hot

>> and this is basic physics because you're

raising entropy. It's just like like

friction there's the same thing

transforming free energy into okay. So

since our head is

an entropy raising thing, our thoughts

are time oriented and because of that we

read a lot of time orientation in the

world. So the time orientation of a lot

of phenomena high level phenomena like

causation like agency is double. It's

because the world itself is oriented and

also because ourself are oriented and

that's created a lot of confusion about

the nature of time because people

usually don't see this double source of

time orientation

and for instance people say um imagine

that in the future in the distant future

the the universe termalizes. So now

you're at maximum entropy. Everything is

uh uh is in equilibrium. So no

phenomenon would distinguish the past

from the future. Okay? And people say,

"Yeah, but if I was there, I could still

feel the time passing." Okay? So

therefore, time exists even at

equilibrium. Where is the mistake? The

mistake is that if you were there and

you're thinking that you were thinking

there,

you're still thinking that there is a

raise of entropy in your brain. If you

were there and you also were in

equilibrium, you couldn't think, you

couldn't record anything, you couldn't

have thought, you couldn't exist, the

neurons wouldn't be firing.

>> So there would be no time at all, not

only in the phenomena, but also in your

thinking because you would not be

thinking. So um

the the beauty of this story in my

opinion is that careful complete

analysis of what is going on shows that

uh if you want to understand complex

phenomena you have to regard them in

their physical

basic description. But also

keeping into account that we use some

way of describing them that depends on

ourself. Not ourself as metaphysical non

non non-physical beings but ourself as

being in the world um like any other

thing. So we are burning candles like

the rest of the biosphere the rest like

the sun. So um this you know this

beautiful Chinese philosophy which is

daoism

um

with this foundational book is swansi

swansi in which uh it's all about this

uh uh similarity of all things. We are

part of nature. We are not something

outside nature and we understand things

why not by trying to understand how why

we're different from nature. imagine

that there is some deep fundamental gap

just part of the flow.

>> Thank you very much Carlo for this

wonderful conversation.

>> Thank you Cliff.